1. Field of the Invention
The present invention generally relates to centralized shared storage systems for collaborative non-linear editing and manipulation of digital video and audio files.
2. Description of the Prior Art
Non-linear video and audio editing systems (NLE's) that can perform random access on the source material are typically set up on independent computer workstations having a means to input digital or analog audio and video as well as software for editing the inputted audio and video.
In such systems, video and sound (e.g., for film and television production) are digitized, or otherwise digital video is imported into the computer for storage on a hard disk or other storage media. Subsequently, the digital media can be manipulated with software such as, Avid's Xpress® Pro and Media Composer Adrenaline, Pinnacle's Liquid Edition, Apple's Final Cut Pro, Optibase's Media 100, Sony Vegas, Canopus Edius, and Adobe Premiere Pro. Various editing tasks can then be performed on the imported video before it is saved, exported to another medium, or encoded for transfer to other storage media, e.g., a CD or DVD.
While a given television or film production facility may have multiple NLE workstations, the digital media files that are stored and accessed by each NLE—video files, audio files, graphics, stills, etc.—typically reside locally on that workstations' internal hard drives or on external hard drives that are directly attached to the workstation.
Several manufacturers offer products that allow multiple NLEs (usually from the manufacturer's own product line) to be attached to a centralized storage network. Attaching NLEs to a common centralized storage network that every user and workstation can access vastly improves the efficiency of editing with NLEs and also allows a workflow that fosters collaboration and creativity. By storing media files in a centralized location, many editors can work simultaneously on the same project without having to duplicate the media files on each system. For example, in a news operation, a reporter can edit a story while an editor creates “coming up next promos” from the same material. In another example from the world of documentaries and feature films, new media files can be added to the system—captured—at one set of workstations while editors edit those files at another set of workstations. Similarly, one editor can tweak the sound for finished parts of the story while another editor works on parts of the story that still need to be edited. Thus, supervisors can review the work of subordinates while the subordinates continue working on a project. Furthermore, editors can use any workstation that's available—because the media files don't have to be directly attached to the workstation that happens to be available.
With all the advantages of attaching NLEs to a common centralized storage network, it would seem that every facility with two or more NLE systems would use centralized storage. However, the high cost of the currently available systems is a significant barrier for many owners of NLE systems. Furthermore, many commercial products that are marketed to provide centralized storage for collaborative editing and manipulation of video and audio files do not provide some key capabilities that users need.
Setting up a comprehensive and effective “home grown” centralized storage system is not a practical alternative in most cases, because shared media files must be stored in such a way that the files are managed and kept safe from accidental erasure and so that the NLE workstations accessing those files do not come into conflict with one another.
For instance, Avid® Technology's products such as Xpress Pro and Media Composer Adrenaline (both Windows and Macintosh versions) scan all the media files they can see on the various storage devices that are accessible to the workstation and then create a database of the clips—writing the database files to the very same folders where the media files are found. If multiple workstations try to access the same media files folder over a network, each workstation will try to rewrite the database files—sometimes causing workstations to crash or corrupt each other's projects. Additionally, the database files for Macintoshes begin with a “dot” (“.”) and the database files for Windows machines do not; thus, Macintoshes ignore the Windows database files, but Windows machines will try to quarantine—remove—the “dot” files because they're not recognized as belonging in the folder.
Another problem arises when capturing new media files onto a system using Xpress DV Xpress Pro, Adrenaline, etc. As new material is being captured from videotape, the digital audio and video media files are temporarily stored in a subfolder called “Creating” and are given temporary names until the capture process is finished. If two or more workstations were capturing at the same time, each workstation would be storing temporary files in the same “Creating” subfolder and trying to give those files the same name—thus, causing a conflict.
Avid® Technology products are not the only NLEs that present such centralized storage difficulties. When working on other industry leading NLEs such as Apple's Final Cut Pro and Adobe Premiere Pro, if multiple users attempt to read and write the same media files on a simple networked volume there is a serious danger that media files can be accidentally—or even maliciously—erased to the detriment of some or all members of the group.
It would be highly desirable, therefore, to provide an economical centralized storage solution that allows multiple users and workstations to access the same media files while avoiding the aforementioned problems of workstation crash, project file corruption, and accidental or malicious erasure of files.
It would further be highly desirable to provide a centralized storage solution that creates a layer of isolation between the multiple users and workstations, and between those users and workstations and the media files they need to manipulate, such that all users and workstations can add to and manipulate a common pool of media files, yet be unable to affect one another in any undesirable way. One way to accomplish this goal would be through utilization of the concept of “file virtualization”—in which a given actual media file can have many different names or locations on a filesystem, or in which given filename can actually stand for a different file or different filename.
It would further be highly desirable to provide a centralized storage solution that would allow incompatible NLEs from different manufacturers to be able to see and manipulate a common set of media files, even though the native names of the media files created by one brand of NLE might normally preclude competing NLEs from recognizing that those files are indeed media files that potentially could be manipulated by the competing brand of NLE. This cross-NLE compatibility could be greatly assisted by file virtualization as well—in which the same media file could have more than one name, each name being tailored so that it can be recognized by specific NLE applications.
File virtualization has been previously used to a limited extent in the context of NLEs accessing a common group of media files over a network, specifically in the case of Rorke Data, Inc.'s ImageSan product (http://www.rorke.com/) and in Tiger Technologie's Meta San product (http://www.metasan.com/). In both cases, these products use virtualization as a means to allow multiple Avid® NLE workstations to each create and access their own unique Media Database files and “Creating” folders from within each media file volume, without letting one Avid® NLE know that other Avid® NLEs have such database files and “Creating” folders there with the same exact names. In both cases, the virtualization aspect of these products involves “client side” software that performs a file- or directory-naming manipulation that is transparent to the NLEs. Thus, for example, when Workstation A attempts to write a certain file (for instance, a Media Database file) in the central location, client software renames that file so that it can coexist with other files that generally would also have the same name. In neither case does file- or directory-naming manipulation take place on the “server side”. Moreover, these solutions only use virtualization in the context of Avid® NLEs, and only for this very limited purpose of allowing multiple Avid® Media Database files and multiple Avid® “Creating” folders to coexist in the same volume so that multiple Avid® editors will not come into conflict with each other as they access the same media volumes (storage spaces).
Moreover, while the use of file “virtualization” has been suggested in the patent literature (see, e.g., United States Patent Publication Nos. 2003/0097276 and 2004/0199578), U.S. Pat. No. 6,195,650, describes the use of symbolic links only as part of a client side solution.
It would thus be highly desirable to provide a centralized collaborative storage system for non-linear editing systems and other devices (e.g., encoders and hardware or software that can record, playback, and/or access digital media files over a network) having a centralized storage media for storing and enabling manipulation of digital video media that implements a server-side solution that enables the linking up of multiple video editing workstations implementing various NLE application platforms and other devices while avoiding the aforementioned problems.
It would further be highly desirable to provide as part of a centralized collaborative storage system a means to allow multiple non-linear editing systems to safely open up and work from and collaborate on the same “Project”. In the world of non-linear editing, Projects are generally understood to encompass “metadata” that refers to media files and not the media files themselves. In their most basic form, Projects include “clips” that refer to entire media files, “subclips” that refer to parts of media files, and “sequences” that refer to media files (in part or in their entirety) all strung together to make a story or program”. In the context of non-linear video editing, the creative work of an editor is generally stored in the Project. Unlike media files, which are typically never modified in the course of editing, Project files are changing all the time because they reflect the editing decisions of an editor. The normal practice of editors therefore is to each maintain their own Projects, because if two or more editors were to open up the same Project from two different non-linear editing workstations (assuming the Project was stored in some central location that could be accessed by more than one editor), one editor would be at great risk for overwriting the changes that others are making, and vice versa. The risk of overwriting changes applies to any information contained in the Project, including settings, bins, sequences, etc. Also, if multiple editors were to open up the same Project file, they would all be confronted with a clutter of information that made it hard to sort out what was being edited by which editor, and who should have modification authority over which metadata.
It would therefore further be highly desirable to provide a centralized collaborative storage system for non-linear editing systems that manages ownership and permissions over different editors' contributions to shared Projects and that implements “symbolic links” to create a virtual file and folder structure that allows multiple non-linear editing systems to collaborate on the same project, keeping work organized so that it is clear which editor is editing what and allowing each editor to maintain his/her own settings for the Project.